Recent increases in public concern for the environment have resulted in various government imposed environmental regulations. Among such regulations are requirements relating to the monitoring of groundwater quality. In response to these requirements, water quality analytic capabilities have been improved and water sampling equipment has been developed. Much has not been effective, however, in obtaining consistent, non-contaminated water samples that are accurately representative of the water system from which the sample is taken.
Groundwater quality is monitored by drilling one or more groundwater monitoring wells in the area where it is necessary to periodically observe the quality of the groundwater. Preferably, a dedicated fluid sampling apparatus is positioned in each of the monitoring wells for obtaining an acceptable sample of the groundwater. A fluid sampling apparatus for use in conjunction with the present invention is disclosed in U.S. Pat. No. 4,489,779 issued Dec. 25, 1984 to Dickenson et al. and U.S. Pat. No. 4,585,060 issued Apr. 29, 1986 to Bernardin et al., the disclosures of which are hereby incorporated by reference.
Prior to obtaining an acceptable water sample from the monitoring well, the monitoring well must be purged approximately three to five times before a representative sample of the groundwater is available. In order to insure that a representative sample of the groundwater is available prior to accepting the sample, prior art sampling equipment operate in one of two ways. First, the equipment will simply purge the well an excessive number of times to insure a representative sample is available. This method proves to be unacceptable due to the excessive amount of water being purged, the excessive length of time involved in purging the well and the fact that it is never actually known if your sample is representative because it is assumed to be representative due to the excessive amount of purging.
The second method available to the prior art sampling equipment is to periodically test a sample until two or three samples have similar readings or until the readings have stabilized. While this method insure that a representative groundwater sample will be accepted, the process proves to be both time consuming and cumbersome.
Accordingly, what is needed is an apparatus which continuously monitors specified parameters of the groundwater as it is being pumped from the monitoring well. By continuously monitoring specified parameters of the groundwater being pumped, it is possible to obtain a representative sample in the shortest amount of time and with the minimum amount of groundwater having to be purged from the well. A groundwater sample is accepted once the specified parameters have stabilized.